GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Power Mirror System Check?

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Go to Step 2

Go to Outside Mirrors System Check

2

  1. Verify that the ignition switch is in the OFF position.
  2. Ground the memory seat diagnostic connector:
  3. • The connector may be taped into the harness .
    • The module beeps once in order to verify that entrance into the mode 1 diagnostic.
    • For a detailed explanation of the memory seat/mirror diagnostic modes, refer to Memory Seats System Check in Seats.
  4. Remove ground from the memory seat diagnostic connector, then ground the connector again within 5 seconds (the module beeps twice in order to verify entrance into the mode 2 diagnostic).
  5. Operate the seat switch and the mirror switch in all directions. The module will beep once for each occurrence of any of the following faults in a position sensor circuit:
  6. • An open
    • A short
    • A discontinuity

Did any switch operations cause the memory seat/mirror module to beep?

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Go to Step 3

Go to Step 8

3

Test or an open or a short in the appropriate circuit:

    • Left mirror left/right - CKT 786 (GRY)
    • Left mirror up/down - CKT 784 (DK GRN)
    • Right mirror left/right - CKT 785 (LT BLU/BLK)
    • Right mirror right/left - CKT 787 (BRN)

Are all of the circuits OK?

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Go to Step 4

Go to Step 7

4

Test CKT 782 (BLK) for an open between the seat position sensor and S341 or the mirror position sensor and S331.

Is CKT 782 OK?

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Go to Step 5

Go to Step 7

5

Test CKT 788 (GRY) for an open between the seat position sensor and S340 or the mirror position sensor and S323.

Is CKT 788 OK?

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Go to Step 6

Go to Step 7

6

  1. Replace the inoperative outside power mirror.
  2. Refer to Power Mirror Replacement

Did you complete the repair?

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Go to Outside Mirrors System Check

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7

Repair the faulty circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Outside Mirrors System Check

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8

  1. The system is functioning properly.
  2. If the symptoms persist, replace the memory seat/mirror module. Refer to Memory Seat Control Module Replacement .

Did you complete the repair?

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Go to Outside Mirrors System Check

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